This invention relates to wheelchairs for handicapped people and, in particular, to the transfer of such wheelchairs into motor vehicles.
Transferring a handicapped person from a wheelchair into a seat of a motor vehicle is frequently a painful and hazardous operation. Vehicles such as vans, small buses, and ambulances are therefore sometimes equipped with taillift mechanisms which enable wheelchairs to be lifted and driven into the back of the vehicle. But such mechanisms are cumbersome and unsuited for use in a normal family-sized car.
In one previous proposal for transferring a wheelchair into a family car, a revolving platform is fitted in the car in place of the normal seat. In use, a ramp is extended from the platform onto the curb or road, and the wheelchair is manoeuvered up the ramp onto the platform. The platform is then revolved to bring the wheelchair to its front-facing position. This mechanism requires a wheelchair which can be adjusted to reduce its height for positioning in the car. Once inside the car, the wheelchair is locked in position and is intended to be used as a driving seat if required.
An advantage of this prior proposal is that the wheelchair occupant can enter or leave the car without having to get out of the wheelchair. On the other hand, the mechanism is complicated and, with the variation in seating layout and size of doorways, it is unlikely that the unit could be fitted in a wide range of cars unless it were separately designed for each car model. Moreover, since the ramp angle would be steep when entry was from the road rather than from the curb, the mechanism would need to be powered externally for many wheelchair occupants who would lack the strength to push themselves up the ramp.
Another prior proposal is described in British patent No. 1,226,402. In this system an invalid chair is lifted from a wheeled base by a hoisting mechanism fixed in the vehicle, it is then swung about a vertical axis of the hoist mechanism so that the chair passes through the door opening, and finally it is lowered into position within the vehicle. The chair is connected to the hoist mechanism by a linkage consisting of upper and lower pairs of arcuate arms, the two upper arms and the two lower arms each being joined at a central pintle, and the arms being locked from pivoting on the central pintles by a rigid stay spanning the two upper arms. The jointed arms in such a mechanism make it difficult to control, the chair being spaced from the hoist mechanism by the length of the double arm linkage until it reaches the door opening, and the linkage then being folded to allow entry of the chair into the vehicle. A further disadvantage is that, whenever the vehicle arrives at its destination, there must be a wheeled base available if the wheelchair occupant is to be able to leave the vehicle.